No abstract

Molecularly imprinted polymers (MIPs) are prepared on the surface of modified silica gel using prometryne as a template, methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as a crosslinker, and 2,2-azobisisobutyronitrile as an initiator. The structure of the MIPs was characterized using SEM and FTIR spectroscopy. The selectivity of the MIPs for the template molecule prometryne was proven by adsorption experiments. Highly selective SPE cartridges of MIP particles were developed and an optimized prometryne procedure was developed for the enrichment and clean-up of prometryne residues in water, soil, and wheat samples. The concentrations of prometryne in the samples were analyzed by HPLC. The average recoveries of prometryne spiked for water at 0.05∼0.8 mg/L were 101.47-106.65% and the RSD was 2.63-4.71%. The average recoveries of prometryne spiked for soil at 0.05∼0.8 mg/L were 87.34-94.91% with the RSD being 2.77-8.41%. The average recoveries of prometryne spiked for wheat plant at 0.2∼2.0 mg/kg were 91.04-97.76% with the RSD being 6.53-10.69%. The method developed here can be regenerated and repeatedly used more than two dozen times.

A molecularly imprinted polymer (MIP) was prepared using chlorsulfuron (CS), a herbicide as a template molecule, methacrylic acid as a functional monomer, ethylene glycol dimethacrylate (EDMA) as a cross-linker, methanol and toluene as a porogen, and 2,2-azobisisobutyronitrile as an initiator. The binding behaviors of the template chlorsulfuron and its analog on MIP were evaluated by equilibrium adsorption experiments, which showed that the MIP particles had specific affinity for the template CS. Solid-phase extraction (SPE) with the chlorsulfuron molecularly imprinted polymer as an adsorbent was investigated. The optimum loading, washing, and eluting conditions for chlorsulfuron molecularly imprinted polymer solid-phase extraction (CS-MISPE) were established. The optimized CS-MISPE procedure was developed to enrich and clean up the chlorsulfuron residue in water, soils, and wheat plants. Concentrations of chlorsulfuron in the samples were analyzed by HPLC-UVD. The average recoveries of CS spiked standard at 0.05~0.2 mg L(-1) in water were 90.2~93.3%, with the relative standard deviation (RSD) being 2.0~3.9% (n=3). The average recoveries of 1.0 mL CS spiked standard at 0.1~0.5 mg L(-1) in 10 g soil were 91.1~94.7%, with the RSD being 3.1~5.6% (n=3). The average recoveries of 1.0 mL CS spiked standard at 0.1~0.5 mg L(-1) in 5 g wheat plant were 82.3~94.3%, with the RSD being 2.9~6.8% (n=3). Overall, our study provides a sensitive and cost-effective method for accurate determination of CS residues in water, soils, and plants.